This invention relates the method of manufacturing spherical rod end bearings having male or female end connections.
In particular, the present invention relates to a method of manufacturing a spherical rod end bearing having an outer member, an intermediate member of yieldable material within and supported by said outer member and an inner race operationally supported by said intermediate member comprising preforming a rod end blank having a ball-like section at one end thereof, flattening the ball-like or ellipsoidal section to form two enlarged faces, each face having an inwardly disposed annular dished portion whereby the material flows uniformly to the outer periphery of the faces to form a uniformly cold formed annular area, removing the inwardly disposed annular dished portion to form a bore through said faces thereby leaving said uniformly cold formed annular area to serve as the outer race member, inserting in said bore said intermediate member and said inner race member, interlocking with mechanical interlocking means said intermediate member and inner race member within said bore to effect the bearing support of said inner race member within said intermediate member.
The prior methods of manufacture of rod end spherical bearings typical includes the forming of spherical member at the end of a rod end blank. The spherical member of the rod end blank is then straddle milled to doubly truncate the spherical end section to generate the "banjo" at the end thereof. This prior art approach requires a number of additional manufacturing steps requiring the use of very expensive machine tools operated by highly skilled and paid machinists.
Additionally, this prior art approach results in a waste of material which end up in a scrap pile in the form of metal shavings. Also, larger types of blank material must be used and stocked.
There have been some attempts to overcome the objections of the prior art including different forming methods using different types of expensive preformed rod end blanks and expensive and complicated dies. An example of such an approach may be found in U.S. Pat. No. 3,248,776 to Brewster, patented May 3, 1966. The Brewster patent is directed to a method of making a self-aligning rod end bearing in which, along other things a spherically enlarged head is formed at one end of a blank, the head is flattened and a cylindrical bore is formed in the flattened end. The inner race member, i.e. the spherical ball, is then placed within the bore opening in "banjo" face and material of the face is coined around the ball to engage and surround the ball. In this method the ball is used as a die and is subjected to the full force of the forming process. Further, the tolerances between the outer race member and inner race member of Brewster would be difficult if not impossible to control. Additionally the outer race member is further deformed by the coining step which might adversely effect its physical characteristics.
The segment of the prior art as typified by Brewster, may be therefore described as a method of manufacturing spherical bearings which is difficult to control and results in a bearing product of dubious quality.